With an in particular self-igniting internal combustion engine it may happen that the combustion in the respective cylinders does not take place at the best possible point of time. This undesired deviation is due to aging effects or manufacturing tolerances. This may result in an increase of exhaust gas discharge, a rise of fuel consumption or also a deterioration of the concentric running of the internal combustion engine.
Methods are known, which detect the exact point of time of the beginning of combustion by means of additionally provided sensors. In DE 33 02 219 A1 as well as in DE 197 49 817 A1 methods are described, which determine the march of pressure in the cylinder internal space by means of pressure sensors. Furthermore, with DE 25 13 289 A1, DE 44 13 473 A1 and DE 196 12 180 C1 methods are disclosed, which detect the impact sound at the outside of the housing of the internal combustion engine. Based on the pressure and/or impact sound signals measured in this way conclusion can be drawn to the beginning of combustion of the internal combustion engine. The sensors additionally necessary with known methods stand for considerable additional expenses.